Aisha Mansoor Ali, Munazzah Rafique, and Zarqa Saleem. “Association of Vitamin D Deficiency to the Risk of Preeclampsia in Saudi Arabia”. Journal of the Pakistan Medical Association (October 6, 2020): 1-14. Accessed April 15, 2021. https://ojs.jpma.org.pk/index.php/public_html/article/view/1545.